A series of compounds that specifically inhibit infectivity of an enveloped virus have been identified. In order to identify the target protein of this inhibition, and as a first step toward mapping the binding site, an affinity labeling procedure has been worked out. The BMS drug is a diazirine containing compound that possesses high potency against the intended virus in tissue culture. The diazirine moiety is photoreactive and will generate a carbene upon illumination that will insert into proximate amino acids. A second objective is to prepare a radiolabelled compound that will be useful for metabolism and pharmacokinetic studies. Funding Source: Industry HPLC Charge: $5742.01 3 days Program Income: $4906.88 2 compounds